scholarly journals Therapeutic and Immunologic Responses Elicited By in Situ Vaccination with CpG, Ibrutinib, and Low-Dose Radiation

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3539-3539
Author(s):  
Tanaya Shree ◽  
Sarah Haebe ◽  
Debra K. Czerwinski ◽  
Grady Day ◽  
Anuja Sathe ◽  
...  

Abstract Introduction: In situ vaccination aims to induce an immune response locally at one tumor site that propagates systemically to all tumor sites. This approach can be effective in indolent lymphoma (Brody et al., JCO 2010, Frank et al., Cancer Discov 2018, Hammerich et al., Nat Med 2019). We designed a novel clinical strategy combining in situ vaccination with systemic ibrutinib, a kinase inhibitor that modulates B and T cells. Our preclinical work had shown that combined intratumoral CpG injection and systemic ibrutinib administration was curative of systemic disease in a mouse lymphoma model, an effect that was T cell dependent (Sagiv-Barfi, Blood, 2015). Here we report the results and correlative data from the Phase I/II clinical trial testing this combination along with local low-dose radiation in adults with recurrent low-grade B cell lymphoma (NCT02927964). Methods: Enrolled patients received intratumoral injections of CpG (SD-101, 3 mg) weekly for 5 doses and local radiation (4Gy in two fractions) to the same site. Daily oral ibrutinib (560mg) began after the second intratumoral injection. Revised Lugano criteria (Cheson et al., JCO, 2014) were used to assess overall radiographic responses to therapy. Distal responses were assessed by excluding the injected site and measuring only non-injected sites. Fine needle aspirates (FNAs) were obtained from CpG-injected and non-injected nodal tumor sites pre- and post-treatment and analyzed by flow cytometry and droplet-based single-cell RNA sequencing (scRNAseq). Results: Among the twenty patients treated on study, median age was 64, 55% were male, and all but one had a diagnosis of follicular lymphoma. All patients were previously treated with an average of 2 lines of therapy, and half had previously received chemotherapy. Adverse events (AEs) were consistent with known effects of ibrutinib (including diarrhea and rash) and of CpG (including fever and flu-like reactions). No drug-related grade 4, serious, or unexpected AEs were observed. As anticipated, all patients experienced tumor reduction at the locally treated site (median 84% reduction). Remarkably, all patients experienced some tumor reduction at non-injected non-irradiated index lesions (median 45%, range 13-100%), suggesting the generation of systemic immune responses (Figure 1A). By Cheson criteria, ten patients achieved an objective response, including one complete response (ORR 50%). Despite an overall improvement in tumor burden, three patients had new or progressing non-index lesions and scored as progressive disease. Treatment induced an expansion of naïve and effector memory T cells and reductions in T follicular helper (Tfh) and activated regulatory T cells (Tregs) at the injected site. T cells with high expression of transcripts related to oxidative phosphorylation (Toxphos) increased preferentially in patients with subsequent clinical tumor reduction (Figure 1B), implicating T cell metabolism in successful generation of immune responses. Analysis of single cell T cell receptor (TCR) sequencing data revealed>300 clones that were comprised of at least 2 cells at each timepoint and which expanded or contracted at least two-fold during treatment. Expanding clones were more likely than contracting clones to be activated or memory T cells and less likely than contracting clones to be Tfh or Tregs (Figure 1C-D). Clone dynamics were often similar at the two sampled tumor sites, reflecting systemic immune responses. Finally, in vitro assays showed treatment-induced expansion of tumor-specific T cells in the peripheral blood of all 6 evaluable patients. Conclusion: The combination of oral ibrutinib, intratumoral CpG, and local low-dose radiation is safe and can generate systemic antitumor immune responses and systemic tumor shrinkage in low-grade B cell lymphoma. Figure 1 Figure 1. Disclosures Shree: Gilead: Other: Spouse's employment. Khodadoust: CRISPR Therapeutics, Nutcracker Therapeutics: Research Funding; Myeloid Therapeutics: Membership on an entity's Board of Directors or advisory committees; Alexion, AstraZeneca Rare Disease: Other: Study investigator. Frank: Kite-Gilead: Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Research Funding; Allogene Therapeutics: Research Funding. Beygi: Kite/Gilead: Current Employment. Levy: GigaGen: Membership on an entity's Board of Directors or advisory committees; Teneobio: Membership on an entity's Board of Directors or advisory committees; Nurix: Membership on an entity's Board of Directors or advisory committees; Dragonfly: Membership on an entity's Board of Directors or advisory committees; Apexigen: Membership on an entity's Board of Directors or advisory committees; Viracta: Membership on an entity's Board of Directors or advisory committees; Spotlight: Membership on an entity's Board of Directors or advisory committees; Immunocore: Membership on an entity's Board of Directors or advisory committees; Walking Fish: Membership on an entity's Board of Directors or advisory committees; Kira: Membership on an entity's Board of Directors or advisory committees; Abintus Bio: Membership on an entity's Board of Directors or advisory committees; Khloris: Membership on an entity's Board of Directors or advisory committees; Virsti: Membership on an entity's Board of Directors or advisory committees; BiolineRx: Membership on an entity's Board of Directors or advisory committees; BeiGene: Membership on an entity's Board of Directors or advisory committees; Quadriga: Membership on an entity's Board of Directors or advisory committees.

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 48-48
Author(s):  
Tanaya Shree ◽  
Michael S. Khodadoust ◽  
Debra K. Czerwinski ◽  
Matthew J. Frank ◽  
Sara Beygi ◽  
...  

Introduction: Local treatment with intratumoral CpG (a toll-like receptor 9 agonist, SD-101) and low-dose radiation can elicit antitumor immune responses and global tumor reduction in patients with low-grade lymphoma (Frank, Cancer Discov, 2018). Ibrutinib compromises B-cell survival by inhibiting Bruton's tyrosine kinase, but also modulates T-cells by inhibiting interleukin-2-inducible T-cell kinase. In a mouse model of lymphoma, ibrutinib plus intratumoral CpG was curative of systemic disease, an effect that was T-cell dependent (Sagiv-Barfi, Blood, 2015). Thus, we initiated a phase I/II clinical trial combining oral ibrutinib, intratumoral CpG and local low-dose radiation in adults with recurrent low-grade lymphoma (NCT02927964). Methods: Enrolled patients received intratumoral injections of CpG (SD-101, 3mg) weekly for 5 doses, starting on the second day of a 2-day course of local radiation (4Gy total) to the same site. Daily oral ibrutinib (560mg) began on day 9. Treatment-emergent adverse events (AEs), ibrutinib dose modifications and adherence were recorded at every visit. Revised Lugano criteria (Cheson et al., JCO, 2014) were used to assess response to therapy, based on CT scans at 3, 6, 12, 18, and 24 months. Fine needle aspirates (FNAs) were obtained from CpG-injected and non-injected nodal tumor sites pre- and post-treatment and analyzed by flow cytometry and single-cell RNA sequencing (scRNAseq). When available, viably preserved tumor and peripheral blood cells were used for in vitro immune response assays. Results: As of July 16, 2020, 18 patients had been treated, with a median follow-up of 12 months. Ten were male and 8 were female. All but one had a diagnosis of follicular lymphoma; one patient had marginal zone lymphoma. All were previously treated with an average of 2 prior lines of therapy. AEs were consistent with known effects of ibrutinib (including diarrhea and rash) and of CpG (including fever and flu-like reaction) with no unexpected AEs to suggest synergistic toxicity. There were no grade 4 or 5 events. AEs led to ibrutinib dose reduction or discontinuation in 2 patients and dose interruption in 6 patients. At the time of analysis, 9 of 18 evaluable patients had achieved a partial response (50% ORR) and 12 of 18 patients experienced at least a 30% reduction in the distant uninjected lesions (Figure 1A). Most responses have been maintained for at least 6 months, many longer (Figure 1B). Flow cytometry revealed decreased T follicular helper cells and increased CD4 and/or CD8 effector T-cells, CD137+ activated T-cells, and NK cells in CpG-injected tumors. Abscopal immune effects in distant non-injected lesions included an increase in Granzyme B+ CD8 T-cells, most prominent after the addition of ibrutinib. scRNAseq data showed significant transcriptional shifts in tumor cells and in tumor-infiltrating T-cells, including signatures of interferon response and T cell activation and cytotoxicity. Finally, in vitro assays showed tumor-specific immune responses in peripheral blood T-cells of all 6 evaluable patients tested thus far. Conclusion: Early data suggest that the combination of oral ibrutinib, intratumoral CpG, and local low-dose radiation is safe and can generate systemic antitumor immune responses and systemic tumor shrinkage in low-grade lymphoma. Disclosures Khodadoust: Seattle Genetics: Consultancy; Kyowa Kirin: Consultancy. Levy:Quadriga: Membership on an entity's Board of Directors or advisory committees; Beigene: Membership on an entity's Board of Directors or advisory committees; GigaGen: Membership on an entity's Board of Directors or advisory committees; Teneobio: Membership on an entity's Board of Directors or advisory committees; Sutro: Membership on an entity's Board of Directors or advisory committees; Checkmate: Membership on an entity's Board of Directors or advisory committees; Nurix: Membership on an entity's Board of Directors or advisory committees; Dragonfly: Membership on an entity's Board of Directors or advisory committees; Abpro: Membership on an entity's Board of Directors or advisory committees; Apexigen: Membership on an entity's Board of Directors or advisory committees; Spotlight: Membership on an entity's Board of Directors or advisory committees; 47 Inc.: Membership on an entity's Board of Directors or advisory committees; XCella: Membership on an entity's Board of Directors or advisory committees; Immunocore: Membership on an entity's Board of Directors or advisory committees; Walking Fish: Membership on an entity's Board of Directors or advisory committees; Viracta: Membership on an entity's Board of Directors or advisory committees.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2825-2825
Author(s):  
Tanaya Shree ◽  
Michael S. Khodadoust ◽  
Debra K. Czerwinski ◽  
Matthew J. Frank ◽  
Wan X. Hong ◽  
...  

Background: In situ vaccination for the treatment of cancer aims to trigger an immune response locally that propagates systemically. We have shown that local treatment with intratumoral CpG (a TLR9 agonist) and low-dose radiation can elicit antitumor immune responses and global tumor shrinkage in patients with low-grade lymphoma (Brody, J Clin Oncol, 2010; Frank, Cancer Discov, 2018). Ibrutinib is a small molecule that compromises B cell survival by inhibiting Bruton's tyrosine kinase (BTK) but also modulates T cell phenotypes by inhibiting interleukin-2-inducible T-cell kinase (ITK). Specifically, there is evidence for ibrutinib-induced skewing of CD4 T-cells toward a Th1 phenotype, which would be expected to promote anti-tumor immunity (Dubovsky, Blood, 2013). In a mouse model of lymphoma, systemic ibrutinib plus intratumoral CpG was curative of systemic disease in all treated mice, an effect that was fully T-cell dependent (Sagiv-Barfi, Blood, 2015). Study Design: To test the hypothesis that ibrutinib will enhance the efficacy of in situ vaccination via its effects on T-cells, we initiated a phase I/II clinical trial combining oral ibrutinib (560mg), intratumoral CpG (SD-101, 3mg) and local low-dose radiation in patients with recurrent low-grade lymphoma (NCT02927964). Patients with follicular lymphoma, marginal zone lymphoma, or indolent mantle cell lymphoma relapsed or refractory to at least one line of prior therapy and with at least one superficial disease site accessible for injection and one independent measurable disease site are eligible. Patients with significant autoimmune disease, recent stroke or intracranial hemorrhage, and those requiring anticoagulation with vitamin K antagonists or chronic treatment with strong CYP3A inhibitors are excluded. The primary outcome of the study is determination of safety of the combination treatment. Secondary outcomes include overall response rate, progression-free survival, and correlative studies of tumor and blood immune populations. Fourteen patients have been enrolled thus far, with a goal enrollment of 21-30 patients. Treatment consists of two consecutive days of low-dose (2 Gy) radiation to the chosen treatment site, followed by 5 weekly injections of CpG into that same site. Daily oral ibrutinib is begun one day after the second CpG injection. CT scans are performed at 3, 6, 12, 18, and 24 months. Common Terminology Criteria for Adverse Events (CTCAE) are used to track treatment-emergent safety events, and Lugano criteria (Cheson, J Clin Oncol, 2014) are used to assess response to therapy. Correlative Studies: Fine needle aspirates (FNAs) are obtained from CpG-injected and non-injected sites pre-treatment and at weeks 2 and 6. Peripheral blood samples are obtained pre-treatment and weeks 2, 4, 6, and at all response assessment timepoints. When available, tumor cells from an excisional biopsy pre-treatment are viably preserved. FNAs and peripheral blood samples from pre-treatment and at weeks 2 and 6 are being analyzed by both flow cytometry and single cell RNA sequencing. For patients for whom viably preserved tumor cells are available, these are co-cultured with autologous peripheral blood T cells in an in vitro immune response assays to test for tumor-specific T-cell activation. Summary: This innovative study combines in situ vaccination and ibrutinib-induced T-cell modulation and incorporates serial sampling of multiple tumors and peripheral blood using minimally invasive procedures, analyzed by methods that allow for deep profiling of treatment-induced changes. This study is ongoing and currently accruing at the Stanford Cancer Center. Disclosures Khodadoust: Corvus Pharmaceuticals: Research Funding. Levy:Spotlight: Membership on an entity's Board of Directors or advisory committees; 47 Inc: Membership on an entity's Board of Directors or advisory committees; XCella: Membership on an entity's Board of Directors or advisory committees; Immunocore: Membership on an entity's Board of Directors or advisory committees; Walking Fish: Membership on an entity's Board of Directors or advisory committees; Five Prime: Membership on an entity's Board of Directors or advisory committees; Corvus: Membership on an entity's Board of Directors or advisory committees; Quadriga: Membership on an entity's Board of Directors or advisory committees; BeiGene: Membership on an entity's Board of Directors or advisory committees; GigaGen: Membership on an entity's Board of Directors or advisory committees; Checkmate: Membership on an entity's Board of Directors or advisory committees; Teneobio: Membership on an entity's Board of Directors or advisory committees; Sutro: Membership on an entity's Board of Directors or advisory committees; Dragonfly: Membership on an entity's Board of Directors or advisory committees; Nurix: Membership on an entity's Board of Directors or advisory committees; Innate Pharma: Membership on an entity's Board of Directors or advisory committees; Abpro: Membership on an entity's Board of Directors or advisory committees; Apexigen: Membership on an entity's Board of Directors or advisory committees; Nohla: Membership on an entity's Board of Directors or advisory committees.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 286-286 ◽  
Author(s):  
Youn H. Kim ◽  
Dita Gratzinger ◽  
Cameron Harrison ◽  
Joshua Brody ◽  
Debra Czerwinski ◽  
...  

Abstract Abstract 286 Background: In a murine model, our in situ vaccination therapy combining tumor antigens with TLR9 agonist cured mice of lymphoma. Our phase I/II study in indolent B-cell lymphoma demonstrated that this in situ vaccination maneuver utilizing local radiation to expose tumor antigens combined with CpG ODN was well-tolerated without treatment limiting toxicities. It induced meaningful systemic clinical responses and tumor-reactive memory CD8 T-cells. In parallel, we explored this in situ vaccination strategy in cutaneous T-cell lymphoma (CTCL), specifically mycosis fungoides (MF). Our objectives were to determine the feasibility and safety and to assess the local and systemic antitumor effects in MF. Methods: Patients with MF stages IA-IVA who failed ≥1 standard therapy were eligible. Immunization site was treated with low-dose radiation (2 Gy × 2 d), bracketed by intratumoral injection of CpG followed by weekly intratumoral CpG × 8. Local (immunized site) and systemic antitumor responses were assessed at wk 0, 2, 4, 8, 12, then monthly until PD/off-study. Clinical response was evaluated by assessing skin disease burden at sites not treated with immunization procedure. Results: Study enrollment was completed with total of 15 patients. Median age was 57 yrs (range 18–71 yrs), 12 of 15 were male. Six patients had stage IB and 9 with stage IIB (3 with large-cell transformation). Median number of prior therapies was 5 with range of 2–9. After the initial 6 patients, a second immunization site was added at wk 4 to enhance systemic response. Total of 5 partial responses were observed (30% OR); 2 of 6 treated with single immunization and 3 of 9 with dual immunization. Median time to response was 8 wks (range 4–12 wks), duration of response 7 wks (range 4–44 wks), and time to progression 20+ wks (range 3–44+ wks). Patients with large-cell transformed MF did not respond. Common toxicities were injection site and flu-like symptoms; mostly grade 1–2 and all transient. No clinical or laboratory findings of any autoimmune disorder were observed. Local tissue tumor/immune responses were assessed by immunostaining. CpG + local radiation treated immunization site showed a significant reduction of CD25+, Foxp3+ T-cells (p<0.01) consisting of MF cells and tumor-infiltrating lymphocytes. Similar reduction in S100+, CD1a+ dendritic cells (DCs) was observed post immunization (p < 0.025). A qualitative analysis suggested more remarkable reduction of CD25+ T-cells and skin DCs in clinical responders vs. non-responders (p= 0.058, 0.121). CpG dose-responsive activation of peripheral blood pDCs was observed in vitro. Conclusions: Our novel in situ vaccination strategy using a combination of intratumoral CpG ODN and low-dose radiation is feasible in CTCL/MF with acceptable toxicities. Depletion of tissue T-regs may be observed at immunized sites. Reduction of skin DCs may suggest cross-priming and migration of DCs to regional lymph nodes. Clinical responses in subset of patients and CpG responsiveness of pDCs may warrant further study with modifications to augment therapeutic effects. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1784-1784
Author(s):  
Khalil Saleh ◽  
Jean-Marie Michot ◽  
Alina Danu ◽  
Julien Lazarovici ◽  
Nadine Khalifé-Saleh ◽  
...  

Abstract Introduction:Low-dose radiation therapy (LD-RT) is a therapeutic option in indolent non Hodgkin B-cell lymphomas (iNHL), usually in the palliative setting. If most iNHL are highly sensitive to radiation therapy, with good local control obtained with a dose of 4 Gy in 2 fractions, little is known about the efficacy and outcome of repetitive courses of LD-RT. We report here the results of a study cohort of repetitive LD-RT in iNHL. Methods : We retrospectively reviewed the records of all iNHL patients treated by two or more courses of LD-RT at Gustave Roussy, between January 1990 and December 2015. Patients received LD-RT as palliative treatment for low-bulky disease, patient's comfort or painful adenopathy. Clinical data, histological types, outcome and treatment lines were collected. Overall survival was the time between lymphoma diagnosis and death from any cause. Last LD-RT follow-up period was the time between the last LD-RT session and latest news. Results: Thirty-five pts were analyzed. Among them, 24 pts (69%) had Follicular Lymphoma (FL), 6 pts (17%) Marginal Zone Lymphoma (MZL), 3 pts (9%) had B-cell primitive Cutaneous Lymphoma Follicular Type (CL-FL) and 2 pts (6%) Nodular Lymphocyte Predominant Hodgkin Lymphoma (NLPHL). At lymphoma diagnosis, median age was 57 years [range 20-80]. Ann Arbor stage was I-II in 18 pts (51%), and III-IV in 17 pts (49%). Patients received a median of 4 therapeutics lines (range 2-11), and 2 LD-RT courses (range 2-6). Median overall survival was 146 months [29-298 months]. Four patients had died: 2 of disease progression and 2 others from concomitant illness (1 cardiac disease and 1 hepatocellular carcinoma). No patient had experienced transformation to diffuse large B cell lymphoma after RT-LD treatments. In the vast majority of cases (31/35; 89%), the LD-RT were successively performed to lymphoma relapse outside irradiation fields. Exclusive repetitive courses of LD-RT without chemotherapy were received by 8/35 (23%) of patients; while 24/35 (69%) patients received repetitive LD-RT alternately with immunotherapies or chemotherapies; and 3/35 (9%) others repetitive LD-RT alternately with standard dose RT. After the second course of LD-RT, 12/35 (34%) patients were managed in watch and wait approach, 6/35 (17%) received another LD-RT and 17/35 (49%) patients had experienced a progressive disease and were treated with immunotherapy or chemotherapy or standard dose radiotherapy. The LD-RT was the last treatment modality in 18/35 (51%) patients with histological types distributed in FL (n=10), MZL (n=5) and CT-FL (n=3). With a median last LD-RT follow up of 32 months [7-177 months], 23/35 (66%) patients remained in complete remission, 9/35 patients (26%) had experienced progressive disease and 3/35 (9%) patients had obtained stable disease. Conclusion: As palliative treatment modality, the repetitive low dose radiation therapy 4 Gy in two fractions could provide alternative option treatment in iNHL. This study support further investigations of this simple, well tolerated and not costly therapy in iNHL, especially in the context of new immunotherapeutic agent's area. Disclosures Michot: Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees. Ribrag:ArgenX: Research Funding; Esai: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Infinity: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Pharmamar: Membership on an entity's Board of Directors or advisory committees; NanoString: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 667-667
Author(s):  
Jennifer Whangbo ◽  
Bryn Falahee ◽  
John Koreth ◽  
Haesook T. Kim ◽  
Sarah Nikiforow ◽  
...  

Abstract Introduction: CD4+CD25+FoxP3+ regulatory T cells (Treg) have broad suppressive activity and play a central role in the maintenance of immune tolerance and prevention of chronic graft-versus-host disease (cGVHD) after allogeneic hematopoietic stem cell transplantation (HSCT). Interleukin-2 (IL-2) is a key growth factor for Treg and we previously reported that daily administration of low-dose IL-2 in patients with refractory cGVHD induces selective expansion of Treg and NK cells. No expansion of CD4 conventional T cells (Tcon) or CD8 T cells was noted. In a Phase 2 study, 64% of patients had clinical responses. Predictors of clinical response included younger age, early IL-2 initiation and a higher Treg:Tcon ratio at study baseline and at week 1 of IL-2 therapy. However, there were no significant differences in overall Treg expansion or plasma IL-2 levels between responders and non-responders during the initial 12 week treatment period. We therefore asked whether functional or gene expression differences in Treg or effector T cells could distinguish clinical response to IL-2. Methods: In vitro Treg suppression assays were performed using cryopreserved patient samples obtained at study baseline and week 6 of IL-2 therapy. CD4+CD25+CD127- Treg were cultured with CellTrace Violet-labeled CD4+CD25- Tcon in the presence of stimulating antibody-coated beads. Proliferation was measured as CellTrace Violet dilution by flow cytometry after 4 days of incubation. All patient samples were tested against the same healthy donor (HD) Treg and Tcon. Differential gene expression between clinical responders and non-responders was examined by RNA Seq analysis of sorted Treg, Tcon, CD8 and NK cells at study baseline and week 4 of IL-2 therapy. Results: To compare Treg cell function between response groups, we tested the ability of patient Treg to suppress the proliferation of HD Tcon. To determine whether there were qualitative differences in effector T cells between the response groups, we measured suppression of patient Tcon by HD Treg. At study baseline, clinical responders appear to have higher Treg suppressive function although the differences between the response groups were not significant due to small sample size (Figure 1A). Patient Tcon in responders and non-responders were similarly suppressed by HD Treg. At week 6 of IL-2 therapy, Treg from non-responders showed significant improvement in suppressive activity against HD Tcon, whereas there was no significant change in suppressive function of Treg from responders (Figure 1B). Thus, despite the lack of clinical improvement in cGVHD symptoms, non-responder Treg show both numeric increase and functional improvement in response to IL-2 therapy. To identify other cell-intrinsic differences that distinguish clinical response to IL-2, we performed RNA Seq on sorted Treg, Tcon, CD8 and NK cells in 3 responders and 3 non-responders. Differentially expressed genes were identified using the DEseq package. There were very few differentially expressed genes between response groups within the pre-treatment Treg, CD8 and NK cell samples (Figure 2). In contrast, 93 genes (92 upregulated, 1 downregulated) with greater than 4-fold difference in expression levels were identified in pre-treatment Tcon samples between responders and non-responders. The top 10 gene ontogeny terms associated with these differentially expressed genes include cell-cell adhesion and ion transport processes. By week 4 of IL-2 therapy, the gene expression profiles of responder and non-responder cells were very similar. There were no differentially expressed genes within Treg, and only 5 within Tcon. Conclusions: In addition to increasing absolute Treg numbers, daily low-dose IL-2 improves Treg suppressive function in patients who do not exhibit clinical cGVHD improvement. Interestingly, RNA Seq results suggest that the determinants of clinical response do not lie within the Treg. Instead, the greatest differences between response groups were detected in pre-treatment CD4 Tcon, implying that lack of clinical response reflects resistance of CD4 effector cells to suppression mediated by Treg in vivo. Further analysis of differentially expressed Tcon genes may help elucidate the mechanisms of resistance to IL-2 therapy in patients with cGVHD. Disclosures Koreth: LLS: Research Funding; prometheus labs inc: Research Funding; kadmon corp: Membership on an entity's Board of Directors or advisory committees; amgen inc: Consultancy; millennium pharmaceuticals: Research Funding; takeda pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Armand:Otsuka: Research Funding; Roche: Research Funding; BMS: Consultancy, Research Funding; Infinity: Consultancy; Merck & Co., Inc.: Consultancy, Research Funding; Sequenta: Research Funding; Sigma Tau: Research Funding; Tensha: Research Funding. Soiffer:Kiadis: Membership on an entity's Board of Directors or advisory committees; Juno: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Ritz:Kiadis: Membership on an entity's Board of Directors or advisory committees.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1933-1933
Author(s):  
Jeffrey S. Miller ◽  
Ryan Bjordahl ◽  
Svetlana Gaidarova ◽  
Sajid Mahmood ◽  
Paul Rogers ◽  
...  

Cancer immunotherapies have resulted in a paradigm shift in therapy. One of the most successful approaches has been administration of antibodies targeting immune checkpoint inhibitors (ICI), such as programmed death-1 (PD-1), that can reinvigorate functionally exhausted T cells. Unfortunately, durable tumor regression is limited to a minority of patients, and relapse remains a significant concern. Combining novel immunotherapies with ICI s a promising strategy to bolster antitumor responses and response rates. Natural killer (NK) cells mediate direct tumor cell lysis, effectively target MHC low or null transformed cells and are key regulators of T cell responses through the production of inflammatory cytokines and chemokines. In many cancers, NK cell numbers are low, and their functional responses are sub-optimal. The use of allogeneic peripheral blood NK cells for immunotherapy has shown significant clinical promise for the treatment of various cancers. However, sourcing NK cells for adoptive cell therapy has been limited by both cell number and quality. Thus, we developed a robust manufacturing system for the differentiation and expansion of high-quality NK cells derived from induced pluripotent stem cells (iPSCs) that can be combined with ICI antibodies for multiple tumor types. To interrogate the ability of iPSC-derived NK cells to synergize with ICI therapy, we developed an in vitro 3D tumor spheroid system to model the combinatorial effects of activated CD3+ T cells, iPSC-derived NK (iNK) cells and ICI blockade for anti-tumor function in a more physiological context than the standard 2D cultures and in real time. Using SKOV-3 (an ovarian cancer line) spheroids as targets in a 160-hour killing assay, we found that iNK cells could mediate significant, but not complete destruction of tumor spheroids (46% tumor reduction). Twice as many activated CD3+ T cells by themselves also induced significant but incomplete tumor spheroid destruction (58% tumor reduction). Combined iNK and activated CD3+ T cells led to robust target cell destruction (71% tumor reduction). Importantly, adding anti-PD-1 antibody (mAb) to activated CD3+ T cells and iNK cells led to near complete elimination of tumor spheroid targets, with >99% tumor reduction. Cytokine and chemokine secretion analyses in co-cultures of activated CD3+ T cells and iNK cells revealed synergistic production of CCL3 and CCL4 for T cell recruitment, and TNF and IFN-γ to augment anti-tumor responses. To determine whether these striking 3D tumor spheroid results simulate the in vivo setting, we injected luciferase-expressing OVCAR8 (a human ovarian cancer line) cells into the peritoneal cavities of immunodeficient NSG mice. Following sublethal irradiation, we treated groups of mice with either anti-PD-1 mAb, activated CD3+ T cells or iNK cells alone or in various combinations. IL-2 was injected i.p. twice weekly for two weeks into all mice except those in the tumor alone group (Figure 1A). In mice that received iNK cells alone, significant tumor control was observed over the first 21 days but was not sustained. Tumor control was similar between groups of mice that received iNK cells and mice that received iNK cells and anti-PD-1 mAb. Mice treated with either anti-PD-1 mAb or activated CD3+ T cells alone exhibited similar rates of tumor growth relative to the untreated group. Modest tumor control was observed in the group of mice that received combined activated CD3+ T cells and anti-PD-1 mAb, though the effect did not reach statistical significance. Durable tumor control past day 21 was observed in groups of mice that received either combined activated CD3+ T cells and iNK cells or activated CD3+ T cells + iNK cells with anti-PD-1 mAb (Figure 1B). Importantly, 50% of mice in the activated CD3+ T cells + iNK cells + anti-PD-1 mAb group exhibited tumor bioluminescence readings well below other treatment group at day 35 (Figure 1C, D). Collectively, these data demonstrate that iNK cells can serve as an off-the-shelf source of high-quality NK cells and synergize with anti-PD-1 ICI therapy to enhance anti-tumor T cell responses in vitro and in vivo, providing a novel immunotherapeutic platform for tumors in which iNK cells, activated CD3+ T cells or anti-PD-1 mAb therapy alone is not sufficiently effective. The current program is under clinical investigation and can be found at clinicaltrials.gov NCT03841110. Disclosures Miller: Moderna: Membership on an entity's Board of Directors or advisory committees; Fate Therapeutics, Inc: Consultancy, Research Funding; CytoSen: Membership on an entity's Board of Directors or advisory committees; OnKImmune: Membership on an entity's Board of Directors or advisory committees; Dr. Reddys Laboratory: Membership on an entity's Board of Directors or advisory committees; GT BioPharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Bjordahl:Fate Therapeutics, Inc.: Employment. Gaidarova:Fate Therapeutics, Inc: Employment. Mahmood:Fate Therapeutics, Inc: Employment. Rogers:Fate Therapeutics, Inc: Employment. Moyar:Fate Therapeutics, Inc: Employment. Blazar:Abbvie Inc: Research Funding; KidsFirst Fund: Research Funding; Childrens' Cancer Research Fund: Research Funding; Leukemia and Lymphoma Society: Research Funding; Regeneron Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Magenta Therapeutics and BlueRock Therapeuetics: Membership on an entity's Board of Directors or advisory committees; Fate Therapeutics, Inc.: Research Funding; Tmunity: Other: Co-Founder; BlueRock Therapeutics: Membership on an entity's Board of Directors or advisory committees; RXi Pharmaceuticals: Research Funding; Alpine Immune Sciences, Inc.: Research Funding; Kamon Pharmaceuticals, Inc: Membership on an entity's Board of Directors or advisory committees; Five Prime Therapeutics Inc: Co-Founder, Membership on an entity's Board of Directors or advisory committees. Kaufman:FATE Therapeutics: Consultancy, Research Funding. Valamehr:Fate Therapeutics, Inc: Employment. Cichocki:Fate Therapeutics, Inc: Research Funding. OffLabel Disclosure: NK cells


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1122-1122 ◽  
Author(s):  
Amy Hughes ◽  
Jade Clarson ◽  
Deborah L White ◽  
David M. Ross ◽  
Timothy P. Hughes ◽  
...  

Abstract Introduction:An attempt at tyrosine kinase inhibitor (TKI) withdrawal in deep molecular remission leads either to treatment free remission (TFR) or early molecular relapse (MolR) in chronic myeloid leukaemia (CML) patients. We hypothesise that immune responses promote sustained TFR and immunological markers may predict response following TFR attempt. Methodology: We studied 54 CML patients (from ALLG trials CML 8, median follow-up 66 mo, and CML 10, median follow-up 24 mo) at baseline on TKI (minimum 24 mo MR4.5) and 3 mo and 6 mo following TKI discontinuation. MolR was defined as any single sample on follow-up with BCR-ABL1 >0.1% or two consecutive BCR-ABL1 positive samples at any value. Effector immune responses of CD56dim natural killer (NK) cells and NK cell receptor repertoire were characterised by flow cytometry and cytotoxic T lymphocyte (CTL) responses to leukaemia-associated-antigens (LAAs) WT1, BMI-1, PR3 and PRAME by interferon-gamma ELISPOT. Immune suppressor regulatory T cells (Treg; CD4+CD25brightCD127-FoxP3+), Granulocytic and Monocytic Myeloid-Derived Suppressor Cells (MDSCs; HLA-DR-Lin-CD11b+CD33+CD66b+CD15+ and HLA-DR-Lin-CD11b+CD33+CD66b-CD14+, respectively), Programmed cell death-1 (PD-1) expression on T cells, NK cells, B cells and Monocytes, and major B cell subsets were characterized by flow cytometry. Results: TFR patients displayed increased CD3-CD56dimCD16bright cytolytic NK cells as a proportion of total lymphocytes at baseline (n=23, 27.1% ± 2.9) vs MolR (n=23, 19.1% ± 2.0, p=0.02). TFR patients displayed a more mature CD56dim CD57+ NK cell phenotype at baseline (74.5% ± 2.2 of total NK cells) vs MolR (66.3% ± 2.7, p=0.04). Extensive characterisation of NK cell receptor repertoire revealed NKG2D activating receptor expression was increased in TFR patients (baseline= 56.8% ± 3.8, 3 mo= 61.4% ± 5.0, 6 mo= 49.9% ± 5.8) vs MolR (baseline= 44.2% ± 3.7, 3 mo= 42.2% ± 5.5, 6 mo= 22.0% ± 8.3, all p=0.02). KIR2DL2/DL3/DS2-positive NK cells were increased in MolR patients at 3 and 6 mo vs TFR. (MolR; 3 mo= 44.8% ± 4.6, 6 mo= 48.8% ± 4.9. TFR; 3 mo= 31.5% ± 4.0 p=0.05, 6 mo= 31.1% ± 2.1, p=0.001). No significant differences were observed in CD56brightCD16-/dim immunoregulatory NK cells, C-type lectin receptor expression (CD94/NKG2A/NKG2C, CD161, CD69), Natural cytotoxicity receptors (NKp30, NKp44, NKp46), CD62L (on T cells and NK cells) and KIR2DL5 expression. No difference in NK Cell-mediated K562 degranulation as a surrogate marker of NK cell function was observed between TFR and MolR patients. Functional CTL immune responses were observed in TFR and MolR patients. BMI-1 CTL responses were increased at baseline in TFR (23%) vs MolR (9%). PR3 CTL responses were not detected in TFR at baseline, 3 mo or 6 mo (0%) vs MolR (baseline= 18%, 3 mo= 50%, 6 mo= 50%). No difference was observed in WT1 or PRAME CTLs. Quantification of immune suppressor cell types revealed decreased Monocytic MDSCs in TFR patients at baseline (10.0% ± 2.3) vs MolR (17.7% ± 3.1, p=0.02). There was no difference in granulocytic MDSCs or Treg between TFR and MolR. No difference in PD-1 expression was observed on NK cells, T cells, B cells and Monocytes. Extensive characterisation of B cell subsets revealed no difference in TFR vs MolR (Table 1). Conclusion: In keeping with STIM and EURO-SKI trials, a threshold level of particular NK cell subsets may be important in maintaining TFR. We found additionally that enhanced NK and CTL effector responses and decreased inhibitory NK KIR2DL2/DL3/DS2 expression, in combination with reduced monocytic MDSC may promote sustained TFR. Methods to enhance nett immune effector responses, such as mature CD56dimCD57+ NK cells and BMI-1 CTL responses or targeting inhibitory KIR may increase TFR success rates. Disclosures White: Ariad: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Ross:Novartis Pharmaceuticals: Honoraria, Research Funding; BMS: Honoraria. Hughes:Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Ariad: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Consultancy, Honoraria. Yong:Celgene: Research Funding; BMS: Honoraria, Research Funding; Novartis: Honoraria, Research Funding.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 917-917
Author(s):  
Marta Coscia ◽  
Michela Capello ◽  
Valentina Griggio ◽  
Federica Linty ◽  
Candida Vitale ◽  
...  

Abstract Abstract 917 In this study we applied the serological proteomics-based approach (SERPA) to identify novel tumor associated antigens (TAA) capable of inducing humoral immune responses in patients with chronic lymphocytic leukemia (CLL). Proteins extracted from the leukemic cells isolated from the peripheral blood of 21 untreated CLL patients were separated by 2-DE electrophoresis and transferred onto membranes by electroblotting to obtain 21 2-DE proteomic maps. Each map was subsequently probed with the corresponding autologous serum collected from the same patient. To verify the CLL-specificity of antibodies (Ab) recognition, 7 out of 21 maps obtained from CLL patients were also probed with sera collected from 7 healthy donors (HD). The Western Blot (WB) performed with sera of CLL patients displayed a total of 45 immunoreactive spots. Only 3 antigen spots were detected in HD sera. For identification, antigen spots in WB were aligned with proteins in 2-DE. The protein spots corresponding to the assigned antigens were excised from the gel, destained and subjected to trypsin digestion. The resulting tryptic fragments were analyzed by peptide mass fingerprint by MALDITOF-MS with MASCOT. All the 45 antigen spots were characterized and consisted of 16 different antigens. Sixteen out of 21 CLL sera (76%) showed immunoreactivity against at least 1 of the 16 identified TAA and 69% of these reactive sera recognized from 2 to 6 different antigens. The IGHV mutational status was available in 20 CLL patients and 12 patients were M, while 8 patients were UM. The reactivity rate and number of WB spots were similar in M and UM patients and did not correlate with other parameters of clinical outcome. Sera from 46% CLL patients exhibited immunoreactivity against a protein which was identified by mass spectrometry as α-Enolase (ENOA). Interestingly, ENOA recognition was CLL specific since none of the sera from HD showed reactivity against this protein. The frequency of ENOA recognition was particularly high in M patients. Indeed, ENOA was recognized from sera of 7 out of 12 M patients (59%), but only from sera of 2 out of 8 UM patients (25%). The ability of ENOA to induce antigen-specific T cell responses was assessed. T cells isolated from the PB of a CLL patient with Ab-based ENOA reactivity were stimulated with autologous monocytes-derived ENOA-pulsed dendritic cells (DC). The results showed that CLL-derived ENOA-pulsed DC stimulated autologous T cells to secrete IFN-gamma. This response was ENOA-specific because it was not induced by unpulsed DC or DC pulsed with an irrelevant protein, and also CLL-specific because IFN-gamma release was not induced when T cells from a HD were stimulated with autologous ENOA-pulsed DC. Altogether, these results indicate that ENOA is capable of eliciting CLL-specific humoral and cellular immune responses. Therefore, ENOA can be considered as an alternative and promising biomarker in CLL, as well as a potential target candidate for immunotherapeutic approaches. Disclosures: Boccadoro: Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen-Cilag: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Massaia:Novartis: Honoraria, Research Funding.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 776-776
Author(s):  
Claire Roddie ◽  
Maeve A O'Reilly ◽  
Maria A V Marzolini ◽  
Leigh Wood ◽  
Juliana Dias Alves Pinto ◽  
...  

Introduction: 2nd generation CD19 CAR T cells show unprecedented efficacy in B-ALL, but several challenges remain: (1) scaling manufacture to meet patient need and (2) feasibility of generating products from lymphopenic patients post allogeneic stem cell transplant (allo-SCT). To overcome these issues we propose: (1) use of the CliniMACS Prodigy (Miltenyi Biotec), a semi-automated cGMP platform that simplifies CAR T cell manufacture and (2) the use of matched donor T cells to overcome the challenge posed by patient lymphopenia, albeit this may come with a heightened risk of graft versus host disease (GvHD). CARD (NCT02893189) is a Phase I study of matched donor derived CD19 CAR T cells generated on the CliniMACS Prodigy in 14 adult patients with relapsed/refractory (r/r) B ALL following allo-SCT. We additionally explore the requirement for lymphodepletion (LD) in the allogeneic CAR T cell setting and report on the incidence of GvHD with this therapy. Methods: Manufacturing: CARD utilises non-mobilised matched donor leucapheresate to manufacture 2nd generation CD19CAR T cells using a closed CliniMACS® Prodigy/ TransACTTM process. Study design: Eligible subjects are aged 16-70y with r/r B ALL following allo SCT. Study endpoints include feasibility of CD19CAR T cell manufacture from allo-SCT donors on the CliniMACS Prodigy and assessments of engraftment and safety including GvHD. To assess the requirement for LD prior to CD19CAR T cells in lymphopenic post-allo-SCT patients, the study is split into Cohort 1 (no LD) and Cohort 2 (fludarabine (30 mg/m2 x3) and cyclophosphamide (300mg/m2 x3)). To mitigate for the potential GvHD risk, cell dosing on study mirrors conventional donor lymphocyte infusion (DLI) schedules and is based on total CD3+ (not CAR T) cell numbers: Dose 1=1x106/kg CD3+ T cells; Dose 2= 3x106/kg CD3+ T cells; Dose 3= 1x107/kg CD3+ T cells. Results: As of 26 July 2019, 17 matched allo SCT donors were leukapheresed and 16 products were successfully manufactured and QP released. Patient demographics are as follows: (1) median patient age was 43y (range 19-64y); (2) 4/17 had prior blinatumomab and 5/17 prior inotuzumab ozogamicin; (3) 7/17 had myeloablative allo SCT and 10/17 reduced intensity allo SCT of which 6/17 were sibling donors and 12/17 were matched unrelated donors. No patients with haploidentical transplant were enrolled. To date, 12/16 patients have received at least 1 dose of CD19CAR T cells: 7/16 on Cohort 1 and 5/16 on Cohort 2 (2/16 are pending infusion on Cohort 2 and 2/16 died of fungal infection prior to infusion). Median follow-up for all 12 patients is 22.9 months (IQR 2.9-25.9; range 0.7 - 25.9). At the time of CAR T cell infusion, 7/12 patients were in morphological relapse with &gt;5% leukemic blasts. Despite this, CD19CAR T cells were administered safely: only 2/12 patients experienced Grade 3 CRS (UPenn criteria), both in Cohort 1, which fully resolved with Tocilizumab and corticosteroids. No patients experienced ≥Grade 3 neurotoxicity and importantly, no patients experienced clinically significant GvHD. In Cohort 1 (7 patients), median peak CAR expansion by flow was 87 CD19CAR/uL blood whereas in Cohort 2 (5 patients to date), median peak CAR expansion was 1309 CD19CAR/uL blood. This difference is likely to reflect the use of LD in Cohort 2. CAR T cell persistence by qPCR in Cohort 1 is short, with demonstrable CAR in only 2/7 treated patients at Month 2. Data for Cohort 2 is immature, but this will also be reported at the meeting in addition to potential mechanisms underlying the short persistence observed in Cohort 1. Of the 10 response evaluable patients (2/12 pending marrow assessment), 9/10 (90%) achieved flow/molecular MRD negative CR at 6 weeks. 2/9 responders experienced CD19 negative relapse (one at M3, one at M5) and 3/9 responders experienced CD19+ relapse (one at M3, one at M9, one at M12). 4/10 (40%) response evaluable patients remain on study and continue in flow/molecular MRD negative remission at a median follow up of 11.9 months (range 2.9-25.9). Conclusions: Donor-derived matched allogeneic CD19 CAR T cells are straightforward to manufacture using the CliniMACS Prodigy and deliver excellent early remission rates, with 90% MRD negative CR observed at Week 6 in the absence of severe CAR associated toxicity or GvHD. Peak CAR expansion appears to be compromised by the absence of LD and this may lead to a higher relapse rate. Updated results from Cohorts 1 and 2 will be presented. Disclosures Roddie: Novartis: Consultancy; Gilead: Consultancy, Speakers Bureau; Celgene: Consultancy, Speakers Bureau. O'Reilly:Kite Gilead: Honoraria. Farzaneh:Autolus Ltd: Equity Ownership, Research Funding. Qasim:Autolus: Equity Ownership; Orchard Therapeutics: Equity Ownership; UCLB: Other: revenue share eligibility; Servier: Research Funding; Bellicum: Research Funding; CellMedica: Research Funding. Linch:Autolus: Membership on an entity's Board of Directors or advisory committees. Pule:Autolus: Membership on an entity's Board of Directors or advisory committees. Peggs:Gilead: Consultancy, Speakers Bureau; Autolus: Membership on an entity's Board of Directors or advisory committees.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 779-779 ◽  
Author(s):  
Zinaida Good ◽  
Jay Y. Spiegel ◽  
Bita Sahaf ◽  
Meena B. Malipatlolla ◽  
Matthew J. Frank ◽  
...  

Axicabtagene ciloleucel (Axi-cel) is an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy approved for the treatment of relapsed or refractory diffuse large B-cell lymphoma (r/r DLBCL). Long-term analysis of the ZUMA-1 phase 1-2 clinical trial showed that ~40% of Axi-cel patients remained progression-free at 2 years (Locke et al., Lancet Oncology 2019). Those patients who achieved a complete response (CR) at 6 months generally remained progression-free long-term. The biological basis for achieving a durable CR in patients receiving Axi-cel remains poorly understood. Here, we sought to identify CAR T-cell intrinsic features associated with CR at 6 months in DLBCL patients receiving commercial Axi-cel at our institution. Using mass cytometry, we assessed expression of 33 surface or intracellular proteins relevant to T-cell function on blood collected before CAR T cell infusion, on day 7 (peak expansion), and on day 21 (late expansion) post-infusion. To identify cell features that distinguish patients with durable CR (n = 11) from those who developed progressive disease (PD, n = 14) by 6 months following Axi-cel infusion, we performed differential abundance analysis of multiparametric protein expression on CAR T cells. This unsupervised analysis identified populations on day 7 associated with persistent CR or PD at 6 months. Using 10-fold cross-validation, we next fitted a least absolute shrinkage and selection operator (lasso) model that identified two clusters of CD4+ CAR T cells on day 7 as potentially predictive of clinical outcome. The first cluster identified by our model was associated with CR at 6 months and had high expression of CD45RO, CD57, PD1, and T-bet transcription factor. Analysis of protein co-expression in this cluster enabled us to define a simple gating scheme based on high expression of CD57 and T-bet, which captured a population of CD4+ CAR T cells on day 7 with greater expansion in patients experiencing a durable CR (mean±s.e.m. CR: 26.13%±2.59%, PD: 10.99%±2.53%, P = 0.0014). In contrast, the second cluster was associated with PD at 6 months and had high expression of CD25, TIGIT, and Helios transcription factor with no CD57. A CD57-negative Helios-positive gate captured a population of CD4+ CAR T cells was enriched on day 7 in patients who experienced progression (CR: 9.75%±2.70%, PD: 20.93%±3.70%, P = 0.016). Co-expression of CD4, CD25, and Helios on these CAR T cells highlights their similarity to regulatory T cells, which could provide a basis for their detrimental effects. In this exploratory analysis of 25 patients treated with Axi-cel, we identified two populations of CD4+ CAR T cells on day 7 that were highly associated with clinical outcome at 6 months. Ongoing analyses are underway to fully characterize this dataset, to explore the biological activity of the populations identified, and to assess the presence of other populations that may be associated with CAR-T expansion or neurotoxicity. This work demonstrates how multidimensional correlative studies can enhance our understanding of CAR T-cell biology and uncover populations associated with clinical outcome in CAR T cell therapies. This work was supported by the Parker Institute for Cancer Immunotherapy. Figure Disclosures Muffly: Pfizer: Consultancy; Adaptive: Research Funding; KITE: Consultancy. Miklos:Celgene: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Kite-Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; AlloGene: Membership on an entity's Board of Directors or advisory committees; Precision Bioscience: Membership on an entity's Board of Directors or advisory committees; Miltenyi Biotech: Membership on an entity's Board of Directors or advisory committees; Becton Dickinson: Research Funding; Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Juno: Membership on an entity's Board of Directors or advisory committees. Mackall:Vor: Other: Scientific Advisory Board; Roche: Other: Scientific Advisory Board; Adaptimmune LLC: Other: Scientific Advisory Board; Glaxo-Smith-Kline: Other: Scientific Advisory Board; Allogene: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Apricity Health: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Unum Therapeutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Obsidian: Research Funding; Lyell: Consultancy, Equity Ownership, Other: Founder, Research Funding; Nektar: Other: Scientific Advisory Board; PACT: Other: Scientific Advisory Board; Bryologyx: Other: Scientific Advisory Board.


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